Our Dimension 4600 XP SP2 with all Windows Updates decided to start locking up and crashing on us every 12-24 hrs. after running problem free 24/7 (almost!) for the past 18 months.  Received this blue screen error:  STOP:c000021a{Fatal) System Error}  The Session Manager Initialization system process terminated unexpectedly with a status of 0x000026c (0x00000000 0x0000000). The system has been shut down.

Did the online chat with Dell, told me to reboot and start tapping F8.  I did this and everything resumed normally, no errors.  Restored back a week, ran a spy ware scan, nothing out of the ordinary found.  More crashes/lockups the next day.  Ran a virus scan using Freedom (provided by Adelphia), found 2, followed suggestion to delete, and again things appeared to be okay.

Came home tonight to another crash.  Tried to restore to 30 days ago, won’t let me, says there have been no changes.

Ran the Dell Crash tool.  Found that tfsnifs.sys (a driver) might need to be updated.  An online search reveals this might be related to Sonic and DLA.  Removed the DLA Windows update, crashed again.

I don’t know what to do next.  I will only call Dell as a last resort, can’t handle that.  If the consensus appears to be to reinstall/rebuild, will someone please post the order to reinstall everything in?

Thanks for reading and any solutions you may have.